1. Field of the Invention
The present invention relates to a display apparatus and a control method thereof, and more particularly, to a display apparatus and a control method thereof, wherein brightness of an output image is increased depending on the remaining amount of a battery or brightness of an input image, and output of a backlight is decreased in correspondence with the brightness of the output image, so that power consumption of the backlight can be reduced while maintaining the brightness of the image.
2. Description of the Related Art
Recently, computer driven programs are provided with a function of increasing brightness of an output image using a gamma correction method and adjusting output of a backlight in correspondence with the brightness.
The gamma correction method is a method of adjusting overall brightness values by setting a brightness function having a gamma value as an index and changing the gamma value.
In the gamma correction method, the brightness function is generally expressed as shown in mathematical expression 1.X=[(X/maximum brightness value)γ]*maximum brightness value  (1)
Thus, since the brightness function has variable “γ” as an index, a brightness value is not corrected by the gamma correction method if brightness of an input image is the same as maximum brightness or has a value of “0”.
In the gamma correction method, an optimum gamma (γ) value suitable for an image should be obtained. However, a process of calculating the optimum gamma value automatically is complicated. In addition, if users themselves determine the optimum gamma value while viewing an output image, its accuracy will be different depending on each individual.
Therefore, the related art described above has following problems.
If brightness of an output image is increased using the gamma correction method, a pixel whose original input brightness has a maximum or minimum brightness value cannot be compensated for decrease in brightness, which is caused by the decrease in the output of backlight. Therefore, boundaries between adjacent pixels are unclear and thus the outline of the image is obscured, whereby the image is degraded.
Further, it is difficult to rapidly detect and apply a gamma value depending on the remaining amount of a battery.